And this is what I ended up with. Had a bit of practise but I suspect the sheet metal is too thin so couple of exhaust brackets and managed too do this so I'm happy with that so far.

Click image to enlarge

Click image to enlarge

Thin metal is hard work when you first start welding, go for something a bit thicker till you get the idea. As for gas I had a BOC account for over 30 years but it got to where they wanted £80 plus a year just to have the bottle of argoshield stood in the garage (better gas than co2 by the way for welding) so switch`d to SGS a while ago now bit of an expense to start with but cheaper in the long run as no rent to pay.